FIG. 14 is a schematic view of a power train system of conventional hybrid vehicle 100 including an engine and a motor generator disclosed in PTL 1.
As shown in FIG. 14, an output shaft of engine 101 is connected to an input shaft of motor generator 103 via torque capacity-variable clutch 105 (an engine-side clutch). An output shaft of motor generator 103 is connected to an input shaft of automatic transmission 107. Tires 111 are connected to an output shaft of automatic transmission 107 via differential gear 109. One of torque capacity-variable clutches in automatic transmission 107 which perform different power transmission in response to a shift state is used as clutch 113 (a transmission-side clutch). Automatic transmission 107 combines power of engine 101 input via clutch 105 and power input from motor generator 103, and outputs the combined power to tires 111.